A light-detection technique may count individual photons to measure intensity of light (e.g., a single photon counting (SPC) technique). For example, incident photons may be counted individually over a period of time to obtain a measure of light intensity and/or flux during an imaging operation.
A circuit to implement the light-detection technique may be complex. The complexity of the circuit may reduce image resolution because of a lower fill factor and/or an increased pixel size. The increased pixel size may prevent a use of the circuit as arrays.
A delay (e.g., a dead-time) may be created after a photon is received until a circuit (e.g., a light-detection circuit) is ready to receive another photon. A reduction of the delay may be prevented because of an implementation of the circuit on a slow semiconductor technology. For example, a solid-state single photon counter that is integrated on a microchip may be implemented in a long channel technology that uses a semiconductor with a lower doping level. The reduction of the delay may also be prevented because of an afterpulse caused by a trapped carrier being released. The afterpulse may be counted as incident photons leading to an inaccuracy in a photon count. As a result, the delay may limit an upper photon count rate, making the light-detection technique unsuitable in an application (e.g., a biomedical application, a military application, a nighttime imaging operation, a low light imaging operation) requiring high-speed processing during the imaging operation.